Resonant antenna



March 9, 1954 J. J. BUBBERS ETAL RESONANT ANTENNA lo MLENQRS BY MM2/fa/Jdwam ATTORNEY Filed Dec. 5 1951 Patented Mar. 9, 1954 UNITED kSTATESPATENT oFiFic'E :RESONANT ANTENNA .Application December 5,1951,.'Se1'ial.No.3259;966

.9 Claims.

This invention relates to a high frequency ane tenna .which may be usedfor television .and other high frequency systems.

The antenna of the instant invention is designed to operate at aresonant frequency so that it is not of the wide-band type as isgenerally used for television purposes where a considerable number ofstations are to be served by a single antenna. On the other hand, theantenna exhibits the high gain and low noise characteristics of narrowband elements.

The antenna of the instant invention is a broadside array constructedaccording to the principles of quarter wave elements rather than theconventional half wave elements. These elements are arranged physicallyso that the antenna requires a minimum of space, a characteristic whichis important in View of current tele vision antenna installationproblems. At the same time, the instant antenna provides simpliiedmounting and installation means in that insulators are substantiallydispensed with. No insulators are required .between a radiator and areector of the instant invention, and none is required between asupporting mast and the complete antenna structure.

Additional desirable characteristics of the antenna will be understoodfrom the following description and drawings in which:

Figure l is an elevational view of the basic form of the instantantenna;

Figure 2 is a perspective view of the antenna which includes areflector; and

Figure 3 is an elevational view of a stacked form of antenna employingthe principles of the instant invention.

The basic form o1" the antenna vis shown in Figure l illustrating it asframe-shaped in the form of a rectangle. Lead in transmission wires areconnected to terminals It and il of the arms I2 and i3 respectively.Arms I2 and I3 are eighth wave elements in respect to the resonant.frequency of the antenna which, for example, may be that of any stationin the television band. Accordingly, arms I2 and I3 together constitutea transverse, centrally gapped or split quarter wave central element,terminals Id and II being connected to its inner ends. Arms I4, I and ISare each a quarter of a wave length long as are the lower arms I1, I3and I9. Aligned arms it and Il comprise one of the long sides of therectangle, aligned arms I5 and I9 comprising the other vlong side. ArmsI5 and It are the short sides.

The above arrangement is such as to employ the electricalcharacteristics of quarter wave ele- (Cl. Z-33.51.)

ments in that they `serveas phase .reversal members at the resonantfrequency. .By virtueof the arrangement disclosed, vra'di'atien'occurs.from fthe horizontal elements 42, 13, I5 and I8 while radiation fromthe arms I4, I6, IFI .and :I9 ris absent because of opposing currentflows. Thus, assuming that the antenna is excited V.at the terminalpoints Ii) vand II as illustrated, point 20 will be negative while point2l will -be positive, a quarter wave length `occurring between these twopoints. At points 2:2 and l231phase reversal takes place so vthat points.'24 and 25 farenegative. Similarly, points .26 and 2-`I are positive.AIt will be evident therefore, that .the currents in arm I5 are .invphase and their nelds `are additive in the plane Lperpendicular to thefigure. The .same condition exists for arms I.2 and lf3 and varim \I B.On the other hand, inasmuch as phase reversal occurs at point 22 of .armI4 so as -to produce current cancellation, .no radiation takes placefrom that arm as indicated by the arrows. The same condition of currentcancellation exists .for arms :16, fI'I and I9.

It will .be seen from the foregoing that radiation ycan `take place only.in one fplane from the horizontal :arms and no radiation takes placefrom the vertical arms. As `above set forth, this results from the useof :quarter Wave :elements and lemploying the phase .reversalcharacteristics thereof to produce :current .cancellation where notydesired and addition in the .plane desired.

Theantenna as above described Vpermits .a simplifed form of reiector 4tobe 'added thereto. The reflector .-30 is shown in Figure 2 andsubstantialhr duplicates the basic form although .it 4may beapproximately 3 percent larger as is conventional. Cross beams -3I and32 are approximately 0.2 wave length long, the customary 4length forsuch cross beams. It Will be noted that points A32's, 34, 35 and .3Scomprise voltagenodes so that no rinsulation at the ends of the crossbeams .is necessary. Hence, any type of fastening may be employed atthese points. .By the same token, a mast 37| may be connected to crossarms 3l and `32 without requiring insulation. Accordingly, themanufacture and installation of the .antenna effects considerableeconomies.

The simplicity of the above described antenna should be evident.Notwithstanding such simplicity, its gain is unusually high.Measurements have been indicated that the Astanding wave ratio withstandard 300 ohm line was extremely low at the resonant :frequency Whilepronounced ygain was manifested relative to a resonant dipole. The beamwidth in the horizontal plane was found to be about 58 at the half powerpoint with only a small minor lobe appearing at the backside of the beamand with substantally no other minor lobes in the horizontal plane.

In Figure 3 is illustrated a stacked form of the antenna. It is onlynecessary to add successive frames having the same dimensions as abovedescribed. The action of the horizontal and vertical elements willfollow the principles above set forth. As in the previous embodiment, areector is employed to make the system uni-directional. The stacked formof antenna, having nve horizontal elements as indicated in Figure 3,exhibits a marked gain over the basic construction. It is found that thehorizontal pattern still has no minor lobes excepting one in back of theantenna which is characteristic of parasitic arrangements and is of noimportance for most applications.

The above description assumes the use of the antenna for horizontallypolarized waves. However, the same principles would apply to verticallypolarized waves it being only necessary to rotate the structure 90 fromthat shown in the drawings, and it is therefore understood that theinvention is directed to both types of polarization.

What is claimed is:

l. A resonant antenna comprising a quarter wave input arm, said inputarm having two spaced inner ends for receiving a pair of lead in wires,a first pair of quarter wave arms extending perpendicularly in onedirection from the respective outer ends of said input arm, a secondpair of quarter wave arms extending outwardly perpendicularly in theopposite direction from the respective outer ends of said input arm, twoadditional quarter wave arms respectively connecting the outer ends ofsaid first pair of arms and said second pair of arms, and a supportingmast connected to one of said two additional quarter wave arms, saidinast connection being free of insulation.

2. An antenna resonant at a predetermined frequency, said antenna beinga frame-shaped structure and comprising two long sides and two shortsides forming a rectangle, said long sides each consisting of twoaligned quarter wave arms at said frequency and said short sides eachconsisting of one quarter wave arm at said frequency, a central,transverse quarter wave arm extending parallel to said short sides andhaving its ends connected to the respective centers of said long sides,means to connect a pair of transmission wires to said central arm, and asupporting mast connected to one of said short sides and being free ofinsulation therefrom.

3. An antenna resonant at a predetermined frequency, said antennacomprising a radiator and a reector spaced therefrom, said radiatorbeing a frame-shaped structure and comprising two long sides and twoshort sides forming a rectangle, said long sides each consisting of twoaligned quarter wave arms at said frequency and said short sides eachconsisting of one quarter wave arm at said frequency, a central,Vtransverse quarter Wave arm extending parallel to said short sides andhaving its ends connected to the respective centers of said long sides,said central arm having a central gap adopted to receive a pair of inputtransmission wires, said reector substantially duplicating the structureof said radiator, the central arm of said reflector being continuous,and a pair of cross beams each extending from the center of one ofthe-radiator short sides to the center of one of the reflector shortsides.

4. An antenna according to claim 3 and wherein all of the connections ofthe arms to each other and to said cross beams are direct and free ofelectrical insulating material.

5. An antenna resonant at a predetermined frequency, said antenna beinga frame-shaped structure and comprising two long sides and two shortsides forming a rectangle, said long sides each consisting of twoaligned quarter wave arms at said frequency and said short sides eachconsisting of one quarter wave arm at said frequency, a central,transverse quarter wave arm extending parallel to said short sides andhaving its ends connected to the respective centers of said long sides,said central arm having a central gap adopted to receive a pair oftransmission wires, and additional quarter wave arms extending infurther alignment with each of said long sides and additional transversearms connecting the ends of said additional quarter wave arms andextending parallel to said short sides.

6. An antenna according to claim 5 and wherein said additional quarterwave arms extend from both of said short sides.

7. An antenna according to claim 6 and wherein the structure recitedcomprises a radiator, said antenna further including a reflector spacedfrom said radiator, said reflector having substantially the same shapeas said radiator, a series of cross beams extending from said radiatorto said reflector at connection points disposed at the centers of atleast two of said cross beams, said connecting points being free ofinsulation.

8. An antenna resonant at a predetermined frequency, said antenna beinga frame-shaped structure and comprising two long sides and two shortsides forming a rectangle, said long sides each consisting of twoaligned quarter wave arms at said frequency and said short sides eachconsisting of one quarter wave arm at said frequency, a central,transverse quarter wave arm extending parallel to said short sides andhaving its ends connected to the respective centers of said long sides,and said central arm having a central gap adopted to receive a pair oftransmission wires, said structure constituting the radiator of aunidirectional antenna and further comprising a reflector spaced fromand substantially duplicating the said frame-shaped structure, saidreflector having its central transverse arm continuous from one longside to the other, and at least one cross beam connecting said radiatorand reflector, said cross beam extending from the center of one of saidshort sides of the radiator to the center of one of the short sides ofthe reector.

9. An antenna according to claim 8 and wherein all the connections ofthe arms to each other and to said cross beam are free of insulation.

JOHN J. BUBBERS. ROBERT E. STUHLER.

References Cited in the file of this patent UNITED STATES PATENTS NumberName Date 1,966,491 Ferrell July 17, 1934 2,082,812 Worrall June 8, 19372,156,661 Wells May 2, 1939 2,163,770 Von Radinger June 27, 19392,283,897 Alford May 26, 1942

